Adjustable suspension-insulator.



S. S. SONNEBORN.

ADJUSTABLE SUSPENSION INSULATOR.

APPLICATION FILED FEB. to. 1911.

1,291,217. Patented Jan.14,1919.

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mammina m um 55 aration between individual insulator units SOL S. SONNEBORN, 0F BROOKLYN, NEW YORK.

-.ADJUSTABLE SUSPENSION-INSULATOR.

Specification of Letters Patent.

Patented Jan. 14, 1919.

Application filed February 10, 1917. Serial No. 147,736.

To all whom it may concern:

Be it known that I, SoL S. SONNEBORN, a citizen of the United States, and a resident of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Adjustable Suspension-Insulators, set forth in the following specification.

This invention rela-tes to suspension insulators of the high tension type.

It is customary in supporting high tension transmission lines, in accordance with one practice,to employ at a point of support an insulator formed by a string of a plurality of high tension suspension insulator units connected in series so that the insulating powerv of each unit will be added to that of' each other unit in the string. In practice, it has been found `to be difficult uniformly to divide the full potential of the line across each insulatorv unit. This diiliculty is partly due tothe fact that the normal potential across each insulator is proportional to capacity current rather than to leakage current when the leakage currents are relativelysmall. The above is on the hypothesis that all the insulator units are identical. What is known as grading has been resorted to more uniformly to distribute anddivide the potential vacross the individual insulator ,units by varying' ,the electro static capacity of the various individual insulator units. This `method of grading hasnecessitated that the diiferent insulator units of a string be physically different one from another,` giving rise to the disadvantage of no-n-interchangeability of parts and the necessity of carrying on hand for repairs a number of each of the different distinct insulator units rather than a number of insulator units all alike, any one of which could be used for repair of any one of the insulator units of a string.

One object of this invention is to provide for grading in a string of insulator units while, at the same time, maintaining identity between each of the units of the string. To this end there is contemplated the provision of means for varying the separation between adjacent units of a string and thereby varying the electro-static capacity between the terminal of one of said units and the distant terminal of the next adjacent unit. A further advantage contemplated in the provision of means for varying the sel is that of providing for the easy adjustment of the arc-over values between units.

A further general object of the invention is to improve suspension insulators in both mechanical and electrical construction. To this end advantage has been taken of the principles of the key-stone of an arch by relatively shapingthe two coperating terminal members of a unit and the intermedilate insulating material, so that the principle of the arch or wedging is employedv rather than the mere reliance upon cohesion and adhesion. ln addition, one novel element contributing toward the improvement in the structure of such an insulator is the formation of an insulating knob which has an opening extending axially through from inner to outer face and comprising' a central cavity opening into a restricted throat so that a terminal having a stem and an enlarged head may be assembled from the outer face of the insulator by thrusting through the stem and afterward insulating the head by lilling the cavity with insulating material.

A further general object is to so shape and combine the terminal parts and insulating material that the contour lines of the insulating material will correspond, at least approximately, to the flow lines of dielectric stress.

The above and furtherv novel elements of the invention will better beV understood by reference to the accompanying claims and the following specification, which herein are directed for purposes of illustration to illustrative embodiments of the invention shown in the accompanying drawings which'form a part hereof, in which like characters designate corresponding parts in'the various figures, and in which Figure 1 is a vertical elevation with parts shown in section and parts broken away of a string'of suspension insulator units embodying the invention; Fig. 2 is a horizontal section, partly in plan, taken through the' line II-II of Fio. 1'; and Fig. 3 is an enlarged vertical -elevation, partly in section, showing a modification.

The embodiment illustrated in Figs. 1 and 2 is preferable when the insulating', material proper is a vitrified product such as porcelain, to the employment of which'other features of the invention are by no means limited. y

ln Fig. l, two insulatorunits band @make up the string A, although it is to be underl stood that the string may comprise as many units as desired. In this string the units are identical and each is shown comprising a body of insulating material 1 such as porcelain, shaped to provide the petticoat 2, flange 3, and knob 4. In the construction illustrated the knob 4 is substantially a solid of revolution, the diameter of the outer walls 5 of which increases from the ledge-6 to the locality 7. In other words, it increases outwardly. The terminal T comprising the connector 8 and the inverted cup-shaped part 9 is shaped so that the inner walls or that part of the inner walls adjacent the outer walls of the knob 4, the diameter of which increases outwardly, are substantially parallel to the lateral Walls of said knob, but so that the inner diameter of the rim 10 of said cup is great enough to pass over It is the lateral walls of the knob and the cup which are relied upon for a mechanical connection, although the formation of the terminal in the shape of a cup provides the additional advantage of a top closure 13, forming a canopy to protect the parts, as will better be understood later. The-complete sealing of the terminal T to the body of insulating material 1 may be effected by casting the collar 14 against the ledge 6 and the rim 10 of the terminal having the circular channel 15. This collar may be formed conveniently out of lead or any other suitable material capable of being cast at a moderate temperature.

An opening C extends axially completely through the knob 4 from the lower or inner face 16 to the outer or upper face 17. The terms inner and outer are used in the claims, because it is contemplated that what is the upper face in the drawings may be the lower face in practice. The opening C comprises the restricted throat 18 in the lower portion of the knob extending to the inner face 16 and the central enlarged cavity 19 which extends up to the outer face 17. The outer portion of the cavity 19 preferably has its walls provided with circular lookin channels 20 and vertical locking channe s 21. v

The more interior portion of the cavity 19 has outwardly flaring walls 22. A cushioning washer 23 of suitable material, which may be lead, is seated in the bottom of the cavity 19. A second terminal U of suitable material (a suitable material for both terminals is malleable iron) comprises two parts, a bolt-like part 25 and a connector part 26., movable relatively to the boltlike part which is adapted to be fixed. In the structure of Figs. 1 and 2 the bolt-like part has a head 27 of octagonal cross-section, the diameter of which increases outwardly so that the lateral walls are substantially parallel to the contiguous inner walls of the cavity 19. The outer face of the head 27 may be provided with key-way channels 28. Extending downwardly or inwardly from the head 27 is a shank 30 externally threaded and internally bored and tapped, as illustrated in Fig. 1. The shank 31 of the connector 26 threads into the shank 30, in which it may be adjustably screwed in or out to vary the distance be tween the connector 26 and the connector 8. Locking means such as the lock-nut 32 may fix the adjustment. A mushroomshaped washer 33 of conducting material such as lead or some other suitable metal, the convex surface of which is directed against the insulating material 1, may be secured in position by engagement with the shank 30. The purpose of this washer is to equalize and distribute the electro-static stress. The terminal structurel U is, of course, assembled before the assembling of the cap-shaped terminal T. When the head 27 is in position, a.l filling 40 of insulating material of high dielectric quality is molded about the head 27, and against the walls 19 about the top of the head 27 into the key-ways 28, and up to and iush with the outer face of the knob 4. The channels 20 increase the surface leakage between the dielectric 40 and the insulating material 1, also aid in locking the filling in place and the channels 21, serve to revent turning of the filling 40, although 1t is by no means essential that the cavity 19 be formed by walls which are surfaces of revolution, as is the case indicated in the drawings.

In Fig. 3 a modification for the terminal U is shown. In this modification the shank 80 of Fig. 1 has substituted for it the shank 300, which is an ordinary bolt shank to which the mushroom-shaped washer 33 is directly engaged. The connector 26 has substituted .for it the connector 260 in the shape of a bail, the upper legs of which are joined to a bored and tapped cross-bar 50 into which the threaded shank 300 threads for axial adjustment and which may be locked in adjusted position by the locknut 320.

It is, of course, to be understood that the advantageous functions of the adjustable terminal U in all its modifications will be present in an insulator, the major insulating material of which is not of necessity porcelain. Moldable insulating material embedding the terminal U into the terminal 'I might be of advantage for certain purposes, although the strength of porcelain both as a dielectric and a mechanical resister against shear are appreciated and porcelain may have actual advantages lending themselves to the key-stone construction embodied in this invention.

Fig. 1 nicely illustrates how the terminal U of insulator unit c may have its axial separation from terminal T of insulator unit b varied merely by screwing in or screwing out the shank 31 of insulator b. A fixed adjustment being accomplished by the lock-nut 32. It being understood that any suitable means as a bolt 60 serves to connect the connector 26of unit b with the connector 8 of unit c.

What is claimed and what is desired to be secured by United States Letters Patent is:

1. In a suspension insulator, a knob of vitreous insulating material the diameter of which increases outwardly; a laterally inclosing metal terminal cap for said knob, the lateral inner walls of which cap are approximately parallel to the lateral walls of said knob; a filling intermediate said cap and said knob for locking the same together on the principle of the keystone of an arch; said knob having an internal cavity open through the top of said knob, the inner lateral walls of which cavity flare outwardly the same as the walls of said knob and cap; a second terminal member having a part located adjacent the flaring walls in said cavity, the lateral wal-ls of which are substantially parallel to the lateral walls of said cavity; and a filling intermediate said part and said lateral walls of said cavity and between said part and said top, whereby said terminals are locked against separation due to suspension strain on the principle of the keystone of an arch. f

2. In a suspension insulator, a knob of insulating material having an opening extending axially through from inner to outer face comprising a restricted throat from the inner face opening into an enlarged cavity intermediate the inner and outer faces; a terminal for embracing the lateral walls of said knob; a second terminal having a stem for 'passing through said throat and an enlarged head to occupy said cavity, a filling of insulating material about and behind said enlarged head; an'd a collar xed to said stem against said inner face of said insulating material and serving to relieve said filling of insulating material from mechanical stresses applied to said stem.

3. An adjustable insulator of the condenser type adapted to form a chain of identical insulators having grading capacity by the adjustment of the individual units, said insulator having two terminals; a body of insulating material 'electrically insulating said terminals one from the other; one of said terminals comprising a fixed part and a movable connector-part; and means for adjusting the axial separation of said connector-part from the other terminal to eiect grading.

4. A system of series insulation for supporting a high potential conductor comprising a plurality of barriers of insulating material; a pair of metal terminal parts anchored to and electrically insulated by each' said barrier and having therewith a condenser function; and conducting means for mechanically securing in any one of various distances of separation a terminal part of one said pair to a terminal part of another said pair whereby the capacity of the system may be locally varied.

5. A series string of substantially identical insulator units, each said unit comprising a pair of separated metallic terminal parts and a separating and sustaining body of insulating material fixing the relative positioning of said pair of terminal parts; and adjustable means for linking one said unit to another at any one `oi various distances of separation to vary capacity.

6. A high tension insulating system comprising a series of insulator units, each said unit comprising two conducting terminal parts and an intermediate body of insulation; and adjustable connecting means for interconnecting said units and adjusting the capacity between units of said series.

7. An insulator comprising a terminal having an enlarged head adapted to be embedded; a threaded outwardly projecting shank; an electro-static stress distributing member screwed upon said shank; and an axially adjustable extension from said shank.

8. In 'an insulator, a terminal having a hollow shank and an enlarged head, said shank being screw-threaded both internally and externally: an electro-static stress distributing member threaded upon the exterior of said shank; and an extension member having threaded engagement with the interior of said shank and capable of axial adjustment.

In witness whereof I have signed my name to this specification; this 31st day of January, 1917.

SOL. S. SONNEBORN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Eatents,

Washington, D. C. 

